And Becker - who won the ATP World Tour Finals three times (1988, 1992, 1995) - says this year's US Open semi-finalist was a deserved victor at London's O2 Arena.

"He lost his momentum at the end of the second set but he started strong in the final set and showed he was the more complete player," Becker said of Wawrinka, who did not drop serve once in the two-hour, 25-minute contest.

"He has a more overall game than Berdych with the backhand slice and he has a big serve when he needs it."

Problem

Becker's fellow Sky Sports analyst, Annabel Croft, was disappointed Berdych was unable to showcase his full range of talents against Wawrinka, but feels the 28-year-old always struggles to deal with his rival's shot-making.

1997 US Open runner-up Greg Rusedski, meanwhile, believes that having come through his maiden World Tour Finals duel unscathed, Wawrinka can push on and press for a place in the knockout stages.

Croft said: "Berdych has got a game that makes him dangerous against so many opponents but he clearly has a bit of a mental problem against Wawrinka as this is the eighth time he has lost to him.

"He is not able to dictate against Stan like he does against other opponents because of Wawrinka's backhand."

On Wawrinka, Rusedski added: "This is a perfect start.

"He is feeling good having got the first win and got rid of the nerves and I think he is only going to go from strength to strength."